Mice teach researchers about prairie
By Bethany Roberts
Photo by Bethany Roberts
Jessica Rodkey (left), a sophomore wildlife and anthropology major from Rossville, Ind., and Kaeda Boyles, a senior wildlife major from Evansville, Ind., write notes about some mice they captured last spring. They are studying the mice to learn more about the overall health of the Purdue Wildlife Area.
Dressed in their rain suits and galoshes, Jessica Rodkey and Kaeda Boyles trekked out to the Purdue Wildlife Area several times throughout the spring, summer and fall before the sun even began to rise.
They used machetes to chop through tall grass that towered over their heads. The morning dew soaked their clothes while they cleared a path step by step to set up their research equipment. On these mornings, they gained perspective on what it means to work hard.
"In these flatlands, the grass is above our heads and the thorns snag us," Rodkey said. "Trapping is a lot of work, but it is still exciting."
Scientific pursuits motivated Boyles, a senior wildlife major from Evansville, Ind., and Rodkey, a sophomore wildlife and anthropology major from Rossville, Ind., to make their morning journeys. The pair trapped, studied and released small mammals as part of a research project for Patrick Zollner, an assistant professor of quantitative ecology. Boyles and Rodkey were particularly interested in the western harvest mouse and white-footed mouse.
Their overall goal was to increase and maintain the health of the prairie in the Purdue Wildlife Area. They trapped small mammals to estimate the species' populations in the prairie.
"The western harvest mice are an indicator species," Rodkey said. "Just as insects are an indicator of water quality, these mice indicate the health of the prairie."
Rodkey started her research for Zollner as a freshman. She focused on the western harvest mouse population, which is a concern in Indiana because they have reappeared in the state only within the last 50 years and exist only in limited numbers.
"My first day out in the fields I was really excited and had so many ideas running through my head," Rodkey said. "We toured different trapping sites, sized up the vegetation and flagged each site where we would be placing traps."
She made grids to help her set traps in the best spots, put ear tags on captured mammals and tracked the mice she captured to their nests and feeding locations after they were released.
Rodkey said her first trapping trip with Zollner was a very interesting experience.
"We had been catching a ton of mice throughout the day, but then the sun went down and we realized neither of us had a flashlight," Rodkey said. "And this just so happened to be during the time cougar rumors had been circulating."
"My heart was pounding as we made it back to our cars," she said. "We don't go after dark anymore."
Zollner and Rodkey brought Boyles onto the project. She studied the white-footed mouse and meadow vole. These species' habitats are affected by prescribed burns, which are fires people intentionally set to maintain a healthy, dynamic prairie. Boyles investigated whether it was more effective for land managers to burn or mow areas to better maintain prime habitats.
She collected data by capturing and recapturing the mammals to estimate the total populations of each species in the prairie.
One of Boyles' most interesting experiences involved a specific capture. Typically, the mice she catches weigh no more than 1.4 ounces, which is about the same as seven quarter coins.
"One day I went to pick up the trap and it was so heavy, I thought I had caught a ton of mice at once," Boyles said. "But then a weasel's head popped up showing its carnivore teeth."
Although Rodkey and Boyles enjoyed working on this research project, they said they encounter obstacles and unpleasant duties. The mice often bit them, the rodents' smells lingered on their hands for a couple of days and setting up the grid was strenuous work.
"We do all these unpleasant things with this research, but when you get out in the fields, you are just so excited," Boyles said.